Conventional solar modules are typically made from materials that are stacked and bonded together to form a support assembly. The support assembly encloses one or more solar cells, which are the electricity-generating component disposed within the solar module. In this configuration, the support assembly serves to both protect the solar cells from damaging environmental elements and facilitate the process of converting solar energy into electricity.
FIG. 1 shows an exploded side-sectional view of a conventional solar module 10, including a cover sheet 12 made from glass. Next to glass cover sheet 12, encapsulants 14 and 18 are provided to encapsulate both sides of a solar cell 16 (e.g., made from either polycrystalline or monocrystalline silicon) to form a “sandwich-like” structure. Adjacent to encapsulant 18, a backsheet is disposed. Backsheet consists of single or multiple layers and performs multiple functions to ensure the longevity and the safety of the solar module. FIG. 1 shows one such backsheet design which includes a polymeric dielectric layer 20 and a polymeric back film 24, which are bonded together by a laminating adhesive 22. Polymeric back film 24 offers protection against moisture, UV, and mechanical damage. Dielectric layer 20 electrically isolates the external portion of solar module 10 from solar cell 16 so that installers, transport personnel, maintenance personnel and fire fighters, who have access to the solar module are not subject to electric shock. This safety feature is particularly important for personnel who are in contact with the solar modules in high voltage systems. Solar module 10 is typically surrounded by an aluminum frame (not shown to simplify illustration) that provides structural integrity, protects the edges of glass cover sheet 12, and provides a convenient attachment point for installation and electrical grounding of the module. In solar module 10, layers 12, 14, 18, 20, 22 and 24, which are disposed between solar cell 16 and an aluminum frame, collectively make up the support assembly.
In the conventional module assembly, glass is a desirable material for cover sheet 12 because it cost-effectively provides structural support to the solar module, protects the solar cells from damage during transportation, installation and use, and also protects the solar cells from environmental elements, such as moisture, snow, hail and wind-borne debris. Additionally, the highly transparent nature of glass allows solar energy to pass through to and impinge upon the solar cells, generating electricity. To maximize and effectively harness solar energy, encapsulants 14 and 18 are substantially transparent to solar wavelengths and are typically made from a polymeric adhesive that bonds the module together. The configuration and various components of solar module 10, as presented in FIG. 1 and discussed above, have not changed since the inception of the solar module design.
Unfortunately, conventional solar modules are heavy for the surface area required and the electrical power obtained, and therefore, suffer from several drawbacks. By way of example, weight and dimensions of the conventional module make its manufacturing, packaging, transportation, installation and support difficult and expensive. The total weight of a conventional solar module and its aluminum frame is between about 18 kg and about 21 kg. Depending on its size and thickness, the glass cover sheet (which typically weighs between about 12 kg and about 15 kg per module) accounts for majority of the module's weight. Moreover, the thickness of a solar module with an aluminum frame is about 55 mm. Furthermore, the fragile nature of the glass cover sheet requires the entire solar module to be securely packaged, adding to the packaging weight and cost.
With respect to shipping, the weight and thickness of the conventional solar modules limit the quantity of modules that may be shipped in a fixed volume of a shipping container. As a result, where a large number of modules are required, there is an increase in the number of shipments, which in turn increases shipping costs. These shipping costs are further exacerbated when installations are conducted in rural destinations or where there is an inadequate transportation infrastructure.
With respect to installation, the weight and size of the conventional module increase the installation costs for residential, commercial and utility-scale applications. A solar module is typically installed on the rooftop of a building or ground structure. Before installation, each module is lifted to a building's roof top and then placed in a desired location. To handle the relatively heavy and large modules, such pre-installation activities require two or more installers for lifting, maneuvering and placing. In some instances, not too uncommon, additional means (e.g., a crane or lift) for lifting modules are necessary that add to the installation costs.
The weight of the module also increases the cost of installation because installation requires a sound structural support system (also referred to as “support mounts”). During the installation process, support mounts are used to rigidly or firmly connect the solar module to a building or a stand-alone facility. Furthermore, support mounts keep the solar module aligned with the sun and prevent the module from being damaged during inclement weather, such as during high winds or heavy snow fall. Even in the absence of harsh weather elements, the heavy solar modules itself places a significant load on the roof and on the support mounts. As a result, the support mounts are designed to firmly secure the modules and withstand the additional load realized from high winds, earthquakes and/or heavy snow fall. To this end, local, state and federal building codes and engineering standards typically regulate the support mounts employed to ensure that they are safe and will perform as intended. A heavier solar module typically requires stronger support mounts that are relatively more expensive to design, build and install.
What are, therefore, needed are novel designs of solar modules and methods of making thereof that do not suffer from the drawbacks encountered by the heavy conventional solar module designs.